Answer:
264 + t ≥ 375
Step-by-step explanation:
The average of Deon's 5 test scores is their sum divided by their number. He wants this value to be 75 or more.
(55 +75 +60 +74 +t)/5 ≥ 75
Multiplying by 5 and collecting terms, we get
264 +t ≥ 375
_____
We might ordinarily stop with the first inequality, but the given answer has no multiplier on "t". So, we need to remove the factor that multiplies "t" in our first inequality.
You will note that we have ended up with a different number than 100 on the right side of the inequality. Though I don't recommend it, if you insist on using 100, you can subtract 275 from the inequality above to make it be ...
-11 +t ≥ 100
(Deon needs a score of 111 on his last test, said to have a maximum score of 100. Deon will not be making a C in this math class.)
